Séminaire ISTerre

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Fluid dynamics of subglacial water environments

jeudi 5 mai 2022 - 11h00

Louis Couston - ENS Lyon
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Subglacial water environments are pockets of liquid water trapped beneath or within ice sheets on Earth or ice crusts on icy moons in the solar system. They are compelling astrobiological targets, hence have attracted significant attention from numerous fields including astronomy, biology and, more recently, fluid dynamics. In this talk, I will provide an overview of subglacial water environments in the solar system and discuss their thermodynamical and hydrodynamical properties. I will discuss the relative importance of geothermal heating and the pressure-dependence of the freezing point on the fluid dynamics of subglacial water environments. I will focus on subglacial water environments on Earth because they will soon be explored (for instance, lake CECs, which lies below 2 km of ice in Antarctica, will be explored/sampled in about 4 years), allowing us to test our predictions based on theory and simulations against field experiments. I will focus on fresh water because most subglacial lakes on Earth have low salinity. I will show that geothermal heating is sufficiently strong to force water motions in most known subglacial lakes on Earth (about 500), despite the existence of a density maximum in fresh water, which tends to stabilize the water column and inhibit vertical motions. In closing I will present some of the outstanding issues relevant to subglacial hydrodynamics research.

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Equipe organisatrice : Géodynamo

Amphithéâtre Killian, Maison des Géosciences, 38400 Saint Martin d'Hères